How do i weight the whole mesh to a single bone?
What you can do is:


Select your mesh, then select your armature using Shift+RightClick
Hit Ctrl+P then choose With Empty Groups
Select your mesh enter Edit Mode then select the vertices/faces you want to be part of a particular bone and then select the bone you want them to be part of from the vertex group panel and hit Assign as shown below. 



Then these vertices will be part of this bone.